Electrical and thermal stability of Ag ohmic contacts for GaN-based flip-chip light-emitting diodes by using an AgAl alloy capping layer

Yoon Tae Hwang; Hyun Gi Hong; Tae Yeon Seong; D. S. Leem; T. Lee; K. K. Kim; J. O. Song

doi:10.1016/j.mssp.2007.01.001

Electrical and thermal stability of Ag ohmic contacts for GaN-based flip-chip light-emitting diodes by using an AgAl alloy capping layer

Yoon Tae Hwang, Hyun Gi Hong, Tae Yeon Seong, D. S. Leem, T. Lee, K. K. Kim, J. O. Song

Department of Materials Science and Engineering

Research output: Contribution to journal › Article › peer-review

13 Citations (Scopus)

Abstract

We have investigated Ag(200 nm)/AgAl(100 nm) ohmic contacts to p-type GaN for near-UV (405 nm) flip-chip light-emitting diodes (LEDs). It is shown that the use of an AgAl alloy capping layer (with 8 at% Al) results in better electrical and optical properties as compared to single Ag contacts when annealed at 430 °C. For example, Ag/AgAl (8 at% Al) contacts give specific contact resistance of 4.6×10^-4 Ω cm² and reflectance of 90% at a wavelength of 405 nm. However, use of an AgAl (with 50 at% Al) layer is not effective. LEDs fabricated with the Ag/AgAl (8 at% Al) reflectors produce higher light output as compared with the ones with single Ag reflectors. Ohmic mechanisms of the Ag/AgAl (8 at% Al) contacts are described and discussed.

Original language	English
Pages (from-to)	14-18
Number of pages	5
Journal	Materials Science in Semiconductor Processing
Volume	10
Issue number	1
DOIs	https://doi.org/10.1016/j.mssp.2007.01.001
Publication status	Published - 2007 Feb

Bibliographical note

Funding Information:
This work was supported by the basic research program of the Korea Science & Engineering Foundation (Grant no. R01-2006-000-10904-0).

Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.

Keywords

Ag reflector
AgAl capping layer
GaN-based flip-chip LEDs
Ohmic contacts
Thermal stability

ASJC Scopus subject areas

Materials Science(all)
Condensed Matter Physics
Mechanics of Materials
Mechanical Engineering

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10.1016/j.mssp.2007.01.001

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title = "Electrical and thermal stability of Ag ohmic contacts for GaN-based flip-chip light-emitting diodes by using an AgAl alloy capping layer",

abstract = "We have investigated Ag(200 nm)/AgAl(100 nm) ohmic contacts to p-type GaN for near-UV (405 nm) flip-chip light-emitting diodes (LEDs). It is shown that the use of an AgAl alloy capping layer (with 8 at% Al) results in better electrical and optical properties as compared to single Ag contacts when annealed at 430 °C. For example, Ag/AgAl (8 at% Al) contacts give specific contact resistance of 4.6×10-4 Ω cm2 and reflectance of 90% at a wavelength of 405 nm. However, use of an AgAl (with 50 at% Al) layer is not effective. LEDs fabricated with the Ag/AgAl (8 at% Al) reflectors produce higher light output as compared with the ones with single Ag reflectors. Ohmic mechanisms of the Ag/AgAl (8 at% Al) contacts are described and discussed.",

keywords = "Ag reflector, AgAl capping layer, GaN-based flip-chip LEDs, Ohmic contacts, Thermal stability",

author = "Hwang, {Yoon Tae} and Hong, {Hyun Gi} and Seong, {Tae Yeon} and Leem, {D. S.} and T. Lee and Kim, {K. K.} and Song, {J. O.}",

note = "Funding Information: This work was supported by the basic research program of the Korea Science & Engineering Foundation (Grant no. R01-2006-000-10904-0). Copyright: Copyright 2008 Elsevier B.V., All rights reserved.",

year = "2007",

month = feb,

doi = "10.1016/j.mssp.2007.01.001",

language = "English",

volume = "10",

pages = "14--18",

journal = "Materials Science in Semiconductor Processing",

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AU - Hwang, Yoon Tae

AU - Hong, Hyun Gi

AU - Seong, Tae Yeon

AU - Leem, D. S.

AU - Lee, T.

AU - Kim, K. K.

AU - Song, J. O.

N1 - Funding Information: This work was supported by the basic research program of the Korea Science & Engineering Foundation (Grant no. R01-2006-000-10904-0). Copyright: Copyright 2008 Elsevier B.V., All rights reserved.

PY - 2007/2

Y1 - 2007/2

N2 - We have investigated Ag(200 nm)/AgAl(100 nm) ohmic contacts to p-type GaN for near-UV (405 nm) flip-chip light-emitting diodes (LEDs). It is shown that the use of an AgAl alloy capping layer (with 8 at% Al) results in better electrical and optical properties as compared to single Ag contacts when annealed at 430 °C. For example, Ag/AgAl (8 at% Al) contacts give specific contact resistance of 4.6×10-4 Ω cm2 and reflectance of 90% at a wavelength of 405 nm. However, use of an AgAl (with 50 at% Al) layer is not effective. LEDs fabricated with the Ag/AgAl (8 at% Al) reflectors produce higher light output as compared with the ones with single Ag reflectors. Ohmic mechanisms of the Ag/AgAl (8 at% Al) contacts are described and discussed.

AB - We have investigated Ag(200 nm)/AgAl(100 nm) ohmic contacts to p-type GaN for near-UV (405 nm) flip-chip light-emitting diodes (LEDs). It is shown that the use of an AgAl alloy capping layer (with 8 at% Al) results in better electrical and optical properties as compared to single Ag contacts when annealed at 430 °C. For example, Ag/AgAl (8 at% Al) contacts give specific contact resistance of 4.6×10-4 Ω cm2 and reflectance of 90% at a wavelength of 405 nm. However, use of an AgAl (with 50 at% Al) layer is not effective. LEDs fabricated with the Ag/AgAl (8 at% Al) reflectors produce higher light output as compared with the ones with single Ag reflectors. Ohmic mechanisms of the Ag/AgAl (8 at% Al) contacts are described and discussed.

KW - Ag reflector

KW - AgAl capping layer

KW - GaN-based flip-chip LEDs

KW - Ohmic contacts

KW - Thermal stability

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Electrical and thermal stability of Ag ohmic contacts for GaN-based flip-chip light-emitting diodes by using an AgAl alloy capping layer

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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